wp_body_open() Error

My Ajaira theme started crashing yesterday out of left field with this error:

Fatal error: Call to undefined function wp_body_open()

I have not made any modifications or custom changes whatsoever to my WordPress site so far this year. This started happening yesterday and I am not sure why.

I have tried reinstalling the theme and I still get the same error. I have had to switch to a different theme to get my site up and running again. (If you look at my site you will see it running with the new theme.) It works fine with a different theme, but I wish to go back to this theme.

Anyone else having this problem? Any ideas on how to fix it?

The page I need help with: [log in to see the link]